Co-Transplantation of Schwann Cells Promotes the Survival and Differentiation of Neural Stem Cells Transplanted into the Injured Spinal Cord

Promotion of Adrenal Pheochromocytoma (PC-12) Cell Proliferation and Outgrowth Using Schwann Cell-Laden Gelatin Methacrylate Substrate

Peripheral nerve injuries cause different degrees of nerve palsy and function loss. Due to the limitations of autografts, nerve tissue engineering (TE) scaffolds incorporated with various neurotrophic factors and cells have been investigated to promote nerve regeneration. However, the molecular mechanism is still poorly understood. In this study, we co-cultured Schwann cells (SCs) and rat adrenal pheochromocytoma (PC-12) cells on 50% degrees of methacryloyl substitution gelatin methacrylate (GelMA) scaffold. The SCs were encapsulated within the GelMA, and PC-12 cells were on the surface. A 5% GelMA was used as the co-culture scaffold since it better supports SCs proliferation, viability, and myelination and promotes higher neurotrophic factors secretion than 10% GelMA. In the co-culture, PC-12 cells demonstrated a higher cell proliferation rate and axonal extension than culturing without SCs, indicating that the secretion of neurotrophic factors from SCs can stimulate PC-12 growth and axonal outgrowth. The mRNA level for neurotrophic factors of SCs in 5% GelMA was further evaluated. We found significant upregulation when compared with a 2D culture, which suggested that this co-culture system could be a potential scaffold to investigate the mechanism of how SCs affect neuronal behaviors.

Decellularized optic nerve functional scaffold transplant facilitates directional axon regeneration and remyelination in the injured white matter of the rat spinal cord

Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury. However, achieving good outcome remains difficult. Our previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion neurites. However, it has not been reported whether this material promotes axonal regeneration in vivo. In the present study, a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann cells. This functional scaffold promoted the directional growth and remyelination of regenerating axons. In vitro, the porcine decellularized optic nerve contained many straight, longitudinal channels with a uniform distribution, and microscopic pores were present in the channel wall. The spatial micro topological structure and extracellular matrix were conducive to the adhesion, survival and migration of neural stem cells. The scaffold promoted the directional growth of dorsal root ganglion neurites, and showed strong potential for myelin regeneration. Furthermore, we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in vivo. Four weeks later, the regenerating axons grew straight, the myelin sheath in the injured/transplanted area recovered its structure, and simultaneously, the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were reduced. Together, these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin regeneration. All procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University (approval No. SYSU-IACUC-2019-B034) on February 28, 2019.

LINGO-1 deficiency promotes nerve regeneration through reduction of cell apoptosis, inflammation, and glial scar after spinal cord injury in mice

Leucine-rich repeat and immunoglobulin domain-containing protein 1 (LINGO-1) is a transmembrane protein that negatively regulates neural regeneration in the central nervous system. LINGO-1 expression is up-regulated after central nerve injury, and is accompanied by cell death. Both LINGO-1 and cell death in the injury microenvironment are thought to limit neural regeneration, but the relationship between LINGO-1 and cell death has not been characterized. To investigate whether LINGO-1 deletion improves the spinal cord microenvironment after spinal cord injury (SCI) and contributes to cell survival, we generated LINGO-1 knockout (KO) mice. These mice and wild-type control mice were subjected to spinal cord transection. Fourteen days after spinal cord transection, cell apoptosis, inflammation, glial scar, and growth of nerve fibers were evaluated by immunostaining. The results showed that LINGO-1 KO mice demonstrated a profound reduction in expression of caspase-3, transferase-mediated deoxyuridine triphosphate biotin nick end labeling (TUNEL), ionized calcium binding adapter molecule 1 (IBA1), glial fibrillary acidic protein (GFAP), and chondroitin sulfate proteoglycans (CSPGs) compared to controls. In contrast, expression of neurofilament (NF) at the SCI site in LINGO-1 KO mice was markedly increased compared to that in wild-type mice. These results suggested that LINGO-1 plays a critical role in the injury microenvironment in processes such as cell death, inflammatory response, and glial scar formation. Importantly, LINGO-1 deletion and a positive microenvironment may exert synergistic effects to promote nerve fiber regeneration. Therefore, inhibition of LINGO-1 may be a therapeutic strategy to promote neural regeneration following SCI.

Combinatorial Therapies After Spinal Cord Injury: How Can Biomaterials Help?

Traumatic spinal cord injury (SCI) results in an immediate loss of motor and sensory function below the injury site and is associated with a poor prognosis. The inhibitory environment that develops in response to the injury is mainly due to local expression of inhibitory factors, scarring and the formation of cystic cavitations, all of which limit the regenerative capacity of endogenous or transplanted cells. Strategies that demonstrate promising results induce a change in the microenvironment at- and around the lesion site to promote endogenous cell repair, including axonal regeneration or the integration of transplanted cells. To date, many of these strategies target only a single aspect of SCI; however, the multifaceted nature of SCI suggests that combinatorial strategies will likely be more effective. Biomaterials are a key component of combinatorial strategies, as they have the potential to deliver drugs locally over a prolonged period of time and aid in cell survival, integration and differentiation. Here we summarize the advantages and limitations of widely used strategies to promote recovery after injury and highlight recent research where biomaterials aided combinatorial strategies to overcome some of the barriers of spinal cord regeneration.

Spinal cord injuries: how could cell therapy help?

INTRODUCTION

Spinal cord injury (SCI) is a devastating condition, where regenerative failure and cell loss lead to paralysis. The heterogeneous and time-sensitive pathophysiology has made it difficult to target tissue repair. Despite many medical advances, there are no effective regenerative therapies. As stem cells offer multi-targeted and environmentally responsive benefits, cell therapy is a promising treatment approach. Areas covered: This review highlights the cell therapies being investigated for SCI, including Schwann cells, olfactory ensheathing cells, mensenchymal stem/stromal cells, neural precursors, oligodendrocyte progenitors, embryonic stem cells, and induced pluripotent stem cells. Through mechanisms of cell replacement, scaffolding, trophic support and immune modulation, each approach targets unique features of SCI pathology. However, as the injury is multifaceted, it is increasingly recognized that a combinatorial approach will be necessary to treat SCI. Expert opinion: Most preclinical studies, and an increasing number of clinical trials, are finding that single cell therapies have only modest benefits after SCI. These considerations, alongside issues of therapy cost-effectiveness, need to be addressed at the bench. In addition to exploring combinatorial strategies, researchers should consider cell reproducibility and storage parameters when designing animal experiments. Equally important, clinical trials must follow strict regulatory guidelines that will enable transparency of results.

Schwann cells promote the capability of neural stem cells to differentiate into neurons and secret neurotrophic factors

The present study investigated whether co-culturing Schwann cells (SCs) with neural stem cells (NSCs) improves viability, direction of differentiation and secretion of brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) in NSCs. The three groups assessed were as follows: SCs, NSCs, and a co-culture of SCs and NSCs. Cellular morphological changes were observed under an inverted phase contrast microscope and quantified. Cells were identified by immunofluorescence staining: S100 for SCs, Nestin for NSCs, microtubule associated protein (Map) 2 and NeuN for neurons and glial fibrillary acidic protein for astrocytes. Cell viability was evaluated by MTT assay. Secretion of BDNF and GDNF was quantified; mRNA expression was quantified by reverse transcription-quantitative polymerase chain reaction. The majority of NSCs in the co-cultured group differentiated into neurons. The cell survival rate of the co-culture group was significantly higher than the other groups on days 3, 5 and 10 (P<0.01). The secretion of BDNF in the co-culture group was significantly higher than NSCs on days 3, 5 and 7 (P<0.05), while the amount of GDNF in co-culture was significantly higher than both NSCs and SCs on day 1 (P<0.05). BDNF and GDNF gene expression in the co-culture group was significantly higher than SCs (P<0.01). Gene expression of Map2 in co-culture group was also significantly higher than both NSC and SC groups (P<0.01). Therefore, co-cultured SCs and NSCs promote differentiation of NSCs into neurons and secrete higher levels of neurotropic factors including BDNF and GDNF.

The efficacy of Schwann cell transplantation on motor function recovery after spinal cord injuries in animal models: A systematic review and meta-analysis

AIM

This article aimed to assess the efficacy of Schwann cell transplantation on motor function recovery in animal model of spinal cord injuries via meta-analysis.

METHODS

An extended search was carried out in the electronic databases of Medline (via PubMed), EMBASE (via OvidSP), CENTRAL, SCOPUS, Web of Science (BIOSIS), and ProQuest. Finally, 41 eligible studies conducted on 1046 animals including 517 control animals and 529 transplanted animals were included in the meta-analysis. Pooled standardized mean difference (SMD) and odds ratio (OR) with 95% confidence interval (95% CI) were reported.

RESULTS

The findings showed that treatment with Schwann cells leads to a modest motor function recovery after spinal cord injury (SMD=0.85; 95% CI: 0.63-1.07; p<0.001). Transplantation of these cells in acute phase of the injury (immediately after the injury) (OR=4.30; 95% CI: 1.53-12.05; p=0.007), application of mesenchymal/skin-derived precursors (OR=2.34; 95% CI: 1.28-4.29; p=0.008), and cells with human sources are associated with an increase in efficacy of Schwann cells (OR=10.96; 95% CI: 1.49-80.77; p=0.02). Finally, it seems that the efficacy of Schwann cells in mice is significantly lower than rats (OR=0.03; 95% CI: 0.003-0.41; p=0.009).

CONCLUSION

Transplantation of Schwann cells can moderately improve motor function recovery. It seems that inter-species differences might exist regarding the efficacy of this cells. Therefore, this should be taken into account when using Schwann cells in clinical trials regarding spinal cord injuries.

Cell Transplantation and Neuroengineering Approach for Spinal Cord Injury Treatment: A Summary of Current Laboratory Findings and Review of Literature

Spinal cord injury (SCI) can cause severe traumatic injury to the central nervous system (CNS). Current therapeutic effects achieved for SCI in clinical medicine show that there is still a long way to go to reach the desired goal of full or significant functional recovery. In basic medical research, however, cell transplantation, gene therapy, application of cytokines, and biomaterial scaffolds have been widely used and investigated as treatments for SCI. All of these strategies when used separately would help rebuild, to some extent, the neural circuits in the lesion area of the spinal cord. In light of this, it is generally accepted that a combined treatment may be a more effective strategy. This review focuses primarily on our recent series of work on transplantation of Schwann cells and adult stem cells, and transplantation of stem cell-derived neural network scaffolds with functional synapses. Arising from this, an artificial neural network (an exogenous neuronal relay) has been designed and fabricated by us—a biomaterial scaffold implanted with Schwann cells modified by the neurotrophin-3 (NT-3) gene and adult stem cells modified with the TrkC (receptor of NT-3) gene. More importantly, experimental evidence suggests that the novel artificial network can integrate with the host tissue and serve as an exogenous neuronal relay for signal transfer and functional improvement of SCI.

Autocrine fibronectin from differentiating mesenchymal stem cells induces the neurite elongation in vitro and promotes nerve fiber regeneration in transected spinal cord injury

Extracellular matrix (ECM) expression is temporally and spatially regulated during the development of stem cells. We reported previously that fibronectin (FN) secreted by bone marrow mesenchymal stem cells (MSCs) was deposited on the surface of gelatin sponge (GS) soon after culture. In this study, we aimed to assess the function of accumulated FN on neuronal differentiating MSCs as induced by Schwann cells (SCs) in three dimensional transwell co‐culture system. The expression pattern and amount of FN of differentiating MSCs was examined by immunofluorescence, Western blot and immunoelectron microscopy. The results showed that FN accumulated inside GS scaffold, although its mRNA expression in MSCs was progressively decreased during neural induction. MSC‐derived neuron‐like cells showed spindle‐shaped cell body and long extending processes on FN‐decorated scaffold surface. However, after blocking of FN function by application of monoclonal antibodies, neuron‐like cells showed flattened cell body with short and thick neurites, together with decreased expression of integrin β1. In vivo transplantation study revealed that autocrine FN significantly facilitated endogenous nerve fiber regeneration in spinal cord transection model. Taken together, the present results showed that FN secreted by MSCs in the early stage accumulated on the GS scaffold and promoted the neurite elongation of neuronal differentiating MSCs as well as nerve fiber regeneration after spinal cord injury. This suggests that autocrine FN has a dynamic influence on MSCs in a three dimensional culture system and its potential application for treatment of traumatic spinal cord injury. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1902–1911, 2016.

Fabrication and evaluation of PLLA multichannel conduits with nanofibrous microstructure for the differentiation of NSCs in vitro

Nerve conduits (NCs) with multiple longitudinally aligned channels, being mimicking the natural nerves anatomical structure, have been attracted more and more attentions. However, some specific structural parameters of a conduit that would be beneficial for further improvement of neural tissue regeneration were not comprehensively considered. Using a systematized device and combining low-pressure injection molding and thermal-induced phase separation, we fabricated 33-channel NCs (outer diameter 3.5 mm, channel diameter 200 μm) with different well-defined microscopic features, including NCs with a nano-fibrous microstructure (NNC), NCs with microspherical pores and nano-fibrous pore walls (MNC), and NCs with a ladder-like microstructure (LNC). The porosities of these NCs were ∼90% and were independent of the fine microstructures, whereas the pore size distributions were clearly distinct. The adsorption of bovine serum albumin for the NNC was a result of having the highest specific surface area, which was 3.5 times that of the LNC. But the mechanical strength of NNC was lower than that of two groups because of a relative high crystallinity and brittle characteristics. In vitro nerve stem cells (NSCs) incubation revealed that 14 days after seeding the NSCs, 31.32% cells were Map2 positive in the NNC group, as opposed to 15.76% in the LNC group and 23.29% in the MNC group. Addition of NGF into the culture medium, being distinctive specific surface area and a high adsorption of proteon for NNC, 81.11% of neurons derived from the differentiation of the seeded NSCs was obtained. As a result of imitating the physical structure of the basement membrane of the neural matrix, the nanofibrous structure of the NCs has facilitated the differentiation of NSCs into neurons.

Preliminary report of multiple cell therapy for patients with multiple system atrophy

The aim of this study is to explore the safety and therapeutic effect of multiple cell transplantations on patients with multiple system atrophy. Ten patients suffering from multiple system atrophy were treated by multiple cell transplantations from August 2005 to March 2011. They were six males and four females, with an average age of 51.90 ± 12.92 years (23-66 years). Multiple cell types were transplanted by intravenous, intrathecal, and intracranial routes; for example, 0.4-0.5 × 10(6)/kg umbilical cord mesenchymal cells by intravenous drip, intrathecal implantation of 2.0 × 10(6) Schwann cells and 2.0-5.0 × 10(6) neural progenitor cells through cerebellar cistern puncture, or 2 × 10(6) olfactory ensheathing cells and 4 × 10(6) neural progenitor cells injected into key points for neural network restoration (KPNNR). The neurological function was assessed before and after treatment with the International Cooperative Ataxia Rating Scale (ICARS) by the World Federation of Neurology and the Unified Multiple System Atrophy Rating Scale (UMSARS). The patients achieved neurological function amelioration after treatment, which included improvements in walking ability, gaits, standing, speech, and muscular tension; the ICARS score decreased from a preoperative 46.30 ± 14.50 points to postoperative 41.90 ± 18.40 points (p = 0.049). The UMSARS score decreased from preoperative 50.00 ± 20.65 points to postoperative 46.56 ± 23.05 points (p = 0.037). Among them, two patients remained stable and underwent a second treatment 0.5-1 year after the first therapy. After treatment, five patients were followed up for more than 6 months. Balance and walking ability improved further in four patients, while one patient remained stable for over 6 months. In conclusion, a strategy of comprehensive cell-based neurorestorative therapy for patients with multiple system atrophy is safe and appears to be beneficial. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.

The potential for cellular therapy combined with growth factors in spinal cord injury

Any traumatic spinal cord injury (SCI) may cause symptoms ranging from pain to complete loss of motor and sensory functions below the level of the injury. Currently, there are over 2 million SCI patients worldwide. The cost of their necessary continuing care creates a burden for the patient, their families, and society. Presently, few SCI treatments are available and none have facilitated neural regeneration and/or significant functional improvement. Research is being conducted in the following areas: pathophysiology, cellular therapies (Schwann cells, embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, olfactory ensheathing cells), growth factors (BDNF), inhibitory molecules (NG2, myelin protein), and combination therapies (cell grafts and neurotrophins, cotransplantation). Results are often limited because of the inhibitory environment created following the injury and the limited regenerative potential of the central nervous system. Therapies that show promise in small animal models may not transfer to nonhuman primates and humans. None of the research has resulted in remarkable improvement, but many areas show promise. Studies have suggested that a combination of therapies may enhance results and may be more effective than a single therapy. This paper reviews and discusses the most promising new SCI research including combination therapies.

Cotransplantation of Human Embryonic Stem Cell-Derived Neural Progenitors and Schwann Cells in a Rat Spinal Cord Contusion Injury Model Elicits a Distinct Neurogenesis and Functional Recovery

Cotransplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when cocultured with SCs in vitro and cotransplanted in a rat acute model of contused SCI. Cocultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs + SCs) relative to the vehicle and control groups. We also observed that animals receiving cotransplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation 5 weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the cotransplanted group when compared to the individual hESC-NP-grafted group. These findings have demonstrated that the cotransplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery.

Implantation of adult bone marrow-derived mesenchymal stem cells transfected with the neurotrophin-3 gene and pretreated with retinoic acid in completely transected spinal cord

Implantation of marrow-derived mesenchymal stem cells (MSCs) is the most promising therapeutic strategy for the treatment of spinal cord injury (SCI), especially because of their potential for clinical application, such as the avoidance of immunologic rejection, their strong secretory properties, and their plasticity for developing into neural cells. However, the recovery from SCI after MSC implantation is minimal due to their limited capacity for the reduction of cystic cavitation, for the axonal regeneration and their uncertain neural plasticity in the spinal cord. We previously pretreated MSCs with all-trans retinoic acid (RA) in vitro. Then we genetically modified them to overexpress neurotrophin-3 (NT-3) via a recombinant adenoviral vector (Adv). This combined treatment not only permitted more neuronal differentiation of MSCs, but stimulated more NT-3 secretion prior to grafting, according to our previous and present results. When these cells were implanted into the transected spinal cord of rats, the animals had some improvement (both functionally and structurally), including the recovery of hindlimb locomotor function, shown by the highest Basso, Beattie, and Bresnahan (BBB) scores, as well as dramatically reduced cavity volume, clear axonal regeneration and more neuronal survival. In contrast, simple MSC implantation is not a very effective therapy for spinal transection. However, the neuronal differentiation of MSCs after treatment with a combination of Adv-mediated NT-3 gene transfer and RA was only mildly improved in vivo.

Electro-acupuncture promotes survival, differentiation of the bone marrow mesenchymal stem cells as well as functional recovery in the spinal cord-transected rats

Background

Bone marrow mesenchymal stem cells (MSCs) are one of the potential tools for treatment of the spinal cord injury; however, the survival and differentiation of MSCs in an injured spinal cord still need to be improved. In the present study, we investigated whether Governor Vessel electro-acupuncture (EA) could efficiently promote bone marrow mesenchymal stem cells (MSCs) survival and differentiation, axonal regeneration and finally, functional recovery in the transected spinal cord.

Results

The spinal cords of adult Sprague-Dawley (SD) rats were completely transected at T10, five experimental groups were performed: 1. sham operated control (Sham-control); 2. operated control (Op-control); 3. electro-acupuncture treatment (EA); 4. MSCs transplantation (MSCs); and 5. MSCs transplantation combined with electro-acupuncture (MSCs+EA). After 2-8 weeks of MSCs transplantation plus EA treatment, we found that the neurotrophin-3 (NT-3), cAMP level, the differentiation of MSCs, the 5-HT positive and CGRP positive nerve fibers in the lesion site and nearby tissue of injured spinal cord were significantly increased in the MSCs+EA group as compared to the group of the MSCs transplantation or the EA treated alone. Furthermore, behavioral test and spinal cord evoked potentials detection demonstrated a significantly functional recovery in the MSCs +EA group.

Conclusion

These results suggest that EA treatment may promote grafted MSCs survival and differentiation; MSCs transplantation combined with EA treatment could promote axonal regeneration and partial locomotor functional recovery in the transected spinal cord in rats and indicate a promising avenue of treatment of spinal cord injury.

Stem and progenitor cell therapies: recent progress for spinal cord injury repair

Mechanical trauma to the spinal cord is often accompanied by irreversible tissue damage, limited endogenous repair and permanent loss of motor, sensory and autonomic function. The implantation of exogenous cells or the stimulation of endogenous cells, to repopulate and replace or to provide a conducive environment for repair, offers a promising therapeutic direction for overcoming the multitude of obstacles facing successful recovery from spinal cord injury. Although relatively new to the scene of cell based therapies for reparative medicine, stem cells and their progenitors have been labeled as the 'cell of the future' for revolutionizing the treatment of CNS injury and neurodegenerative disorders. The following review examines the different types of stem cells and their progenitors, their utility in experimental models of spinal cord injury and explores the outstanding issues that still need to be addressed before they move towards clinical implementation.

Reknitting the injured spinal cord by self-assembling peptide nanofiber scaffold

In traumatic spinal cord injury, loss of neurological function is due to the inability of damaged axons to regenerate across large, cystic cavities. It has recently been demonstrated that a self-assembled nanofiber scaffold (SAPNS) could repair the injured optical pathway and restore visual function. To demonstrate the possibility of using it to repair spinal cord injury, transplanted neural progenitor cells and Schwann cells were isolated from green fluorescent protein-transgenic rats, cultured within SAPNS, and then transplanted into the transected dorsal column of spinal cord of rats. Here we report the use of SAPNS to bridge the injured spinal cord of rats, demonstrating robust migration of host cells, growth of blood vessels, and axons into the scaffolds, indicating that SAPNS provides a true three-dimensional environment for the migration of living cells.

Recombinant adenovirus vector-mediated functional expression of neurotropin-3 receptor (TrkC) in neural stem cells

We have constructed a recombinant adenovirus expression vector carrying the human neurotrophin-3 (NT-3) receptor TrkC (tyrosine protein kinase C) gene (rAd-TrkC; 2478 bp) and confirmed the expression of the encoded TrkC in green fluorescent protein (GFP)-murine neural stem cells (NSCs) by reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunocytochemistry. The activity of the expressed rAd-TrkC was verified in vitro by evaluating dose-related responses of NSCs to NT-3, a TrkC specific ligand. TrkC-GFP-NSCs had a significantly higher percentage of neuronal differentiation when treated with NT-3 relative to the rAd-LacZ control cells (55.2% vs. 29.8%; P<0.05, chi(2) test). Thus, our rAd-TrkC vector can transfect NSCs and produce functional TrkC receptors to promote neuronal differentiation of NSCs.

Cotransplant of neural stem cells and NT-3 gene modified Schwann cells promote the recovery of transected spinal cord injury

STUDY DESIGN

An animal model of transected spinal cord injury (SCI) was used to test the hypothesis that cografted neural stem cells (NSCs) and NT-3-SCs promote morphologic and functional recoveries of injured spinal cord.

OBJECTIVE

To explore whether cotransplant of NSCs and NT-3-SCs could promote the injured spinal cord repair.

SETTING

Zhongshan Medical College, Sun Yat-sen University, PR China.

METHODS

Female Sprague-Dawley (SD) rats weighing on 200-220 g were used to prepare SCI models. The spinal cord was transected between T(9) and T(10), then NSCs, SCs+NSCs, LacZ-SCs+NSCs, or NT-3-SCs+NSCs were grafted into the transected site.

RESULTS

(1) Part of NSCs could differentiate to neuron-like cells in the transected site and the percentage of differentiation was NT-3-SCs+NSCs group>SCs+NSCs group>NSCs group. (2) In the grafted groups, there were 5-HT, CGRP, and SP positive nerve fibres within the transected site. Some fluorogold (FG)-labeled cells were found in the spinal cord rostral to the transected site, the red nuclei and the inner pyramidal layer of sensorimotor cortex. (3) The cells grafted could enhance the injured neurons survival in inner pyramidal layer of sensorimotor cortex, red nuclei of midbrain, and Clark's nuclei of spinal cord's L1 segment, could decrease the latency and increase the amplitude of cortical somatosensory evoked potential (CSEP) and cortical motor evoked potential (CMEP), and could promote partly structural and functional recovery of the SCI rats.

CONCLUSION

These results demonstrate that cografted NT-3-SCs and NSCs is a potential therapy for SCI.

SPONSORSHIP

This research was supported by Chinese National Key Project for Basic Research (G1999054009), Chinese National Natural Science Foundation (30270700) and Social Developmental Foundation of Guangdong Province (2003C33808) to YS Zeng; Natural Science Foundation of Guangdong Province (04300468) and Medical Science Research Grant of Guangdong Province (A2004081) to JS Guo.